Bayern Munich's only warm-up match before the Bundesliga resumes ended in a 2-1 defeat at second-division Karlsruhe and the sending-off of defender Jerome Boateng on Saturday.

Outgoing Munich manager Pep Guardiola will hope to end his reign in Bavaria on a high after announcing plans to manage in the Premier League next season, but his side made a poor start to his long farewell.

The runaway Bundesliga leaders fell behind when Boubacar Barry handed the home side the lead after 16 minutes, but Arturo Vidal equalised midway through the first-half.

Dimitrios Diamantakos is challenged by Jerome Boateng, who was sent off in the friendly on Saturday

Bayern Munich coach made a raft of substituions in the second half against the Bundesliga 2 outfit Karlsruhe

The goal served to spark Bayern into life as Vidal levelled matters five minutes later with a delightful curled effort from the edge of the box, and Diego Costa then went close to completing the turnaround.

But the interval and the subsequent injury to Rafinha took the sting out of the contest, before referee Daniel Schlager awarded the home side and Nazarov the decisive opportunity to clinch an unlikely victory.

Bayern are seeking an unprecedented fourth straight Bundesliga title before coach Guardiola leaves at the end of the season, with the club still in the chase for the Champions League title and German Cup success.

Bayern kick off the second half of the season on Friday against Hamburger SV. The Bundesliga has been on its winter break for nearly four weeks.